Extras

Question 1

What is a hydatidiform mole?

What causes it?

Answer 1

• “mole” refers to a clump of growing tissue
• it is an abnormal pregnancy that involves a non-viable fertilised egg implanting into the uterus and failing to come to term
• it is often caused by a sperm fertilising an “empty” oocyte that does not contain an original maternal nucleus

Question 2

What type of tissue forms a hydatidiform mole?

Answer 2

• there is an overproduction of trophoblastic tissue
• this produces abnormal masses that are usually benign, but can turn cancerous
• the placenta contains grapelike vesicles that occur when the chorionic villi become distended by fluid

Question 3

How does a hydatidiform mole usually present?

What can it cause false results for?

Answer 3

• usually presents with painless vaginal bleeding in the 4th-5th month of pregnancy
• there may also be:

1. enlarged uterus and/or ovaries
2. hyperemesis
3. hypertension
4. proteinuria

• blood tests will show very high levels of hCG and pregnancy tests will show a false positive result

Question 4

What are the risk factors for hydatidiform mole?

Answer 4

• defects in the egg
• abnormalities within the uterus
• nutritional deficiencies (diet low in protein, folic acid & carotene)
• women <20 and >40 years of age

Question 5

How can hydatidiform mole be detected prenatally?

Answer 5

• it has a characteristic “snowstorm” appearance on USS
• definitive diagnosis requires histopathological examination, which shows increased trophoblast proliferation and enlarging of the chorionic villi

Question 6

What condition can hydatidiform mole potentially progress to?

Answer 6

• there is a risk that it can develop into choriocarcinoma** or an **invasive mole
• an invasive mole may invade so far into the uterine wall that it results in haemorrhage and other complications
• choriocarcinoma is a malignant, rapidly growing and metastatic form of cancer with a poor prognosis

Question 7

What is the bleeding like in placenta praevia?

How does this condition typically present?

Answer 7

• this condition involves “revealed” bleeding, opposed to “concealed”
• this bleeding is bright red and is usually not painful
• it presents as antepartum haemorrhage (APH) or failure of the head to engage at delivery

Question 8

What are the associations of placenta praevia?

Answer 8

• multiparity
• large placentae (twins)
• uterine abnormalities, such as fibroids
• previous uterine surgery
• previous C-section

Question 9

What is meant by placental abruption?

What type of bleeding does this produce?

Answer 9

• this occurs when the placenta separates from the uterus before birth (usually 25 weeks)
• the maternal vessels tear away from the decidua basalis, causing a tear in the uterine tissue
• this produces bleeding that can be “revealed” or “concealed”
• it can be partial or complete
• once the placenta is fully separated from the uterus, it is unable to provide the exchange needed to keep the foetus alive

Question 10

What are the potential causes of placental abruption?

Answer 10

• the cause is unknown, but potential associations include:

1. pre-eclampsia
2. smoking
3. thrombophlebitis
4. previous C-section
5. multiple pregnancies
6. short umbilical cord

Question 11

How does placental abruption typically present?

Answer 11

• presents as antepartum haemorrhage (APH) or maternal shock without bleeding
• there may be associated pre-eclampsia, anuria and DIC
• coagulation abnormalities are usually present
• the uterus is tender and tense
• there is constant pain
• the shock is out of proportion to the visible loss

Question 12

What is the management for a large and small placental abruption?

Answer 12

Small abruption:

• the mother is monitored in hospital until a change in condition or foetal maturity (whichever is first)

Large abruption:

• vaginal delivery can be attempted if the mother is stable
• if not, C-section is performed but this carries a greater risk of DIC
• if the mother is less than 36 weeks pregnant, corticosteroids are given to speed to development of foetal lungs

Question 13

What is meant by velamentous insertion of the umbilical cord?

What condition is this associated with?

Answer 13

• this occurs when the umbilical cord does not insert into the centre of the placenta
• the unprotected umbilical vessels travel in foetal membranes (between amnion and chorion) to reach the placenta
• if the blood vessels lie close to the cervix, this is vasa previa, which carries a risk of rupture during delivery
• the foetus can exsanguinate (be drained of blood) before birth

Question 14

What is vasa previa and how can it be detected prior to birth?

Answer 14

• the umbilical vessels are unprotected** and travel in foetal membranes **near or across the internal opening of the uterus
• the umbilical vessels are at risk of rupture when the supporting membranes rupture
• it is detected on USS - tubular structures are found overlying / in close proximity to the cervix and Doppler is used to confirm that these are foetal vessels
• foetal haemoglobin within vaginal bleeding is diagnostic of this condition

Question 15

What is the treatment for vasa previa?

Answer 15

• women are recommended to have an elective C-section prior to rupture of the membranes (35-36 weeks)
• steroids are given to promote foetal lung development
• an emergency C-section is performed if the patient goes into labour or the membranes rupture

Question 16

What are the risk factors for vasa previa?

Answer 16

1. velamentous insertion of the umbilical cord
2. multiple gestation
3. accessory placental lobes / bilobed placenta
4. IVF pregnancies

Question 17

What is the classic triad of vasa praevia?

What happens if this condition goes undetected?

Answer 17

1. membrane rupture
2. painless vaginal bleeding
3. foetal bradycardia / foetal death

• if it is undetected, the umbilical vessels rupture when the membranes rupture
• there is bleeding from the foetoplacental circulation, resulting in rapid exsanguination of the foetus and delivery of a stillbirth / neonatal death

Question 18

What is pre-eclampsia?

How many pregnancies are affected by this condition?

Answer 18

• a disorder of pregnancy characterised by the onset of hypertension and significant proteinuria
• it begins after 20 weeks of pregnancy and symptoms resolve following delivery of the placenta
• mild pre-eclampsia affects 6% of pregnancies and severe pre-eclampsia affects 1-2%

Question 19

What is thought to be the underlying cause of pre-eclampsia?

How does the appearance of the placenta differ in someone with this condition?

Answer 19

• cause is unknown but it is thought to involve formation of abnormal blood vessels in the placenta and poor trophoblastic invasion into the endometrium
• an abnormally implanted placenta is a significant predisposing factor to pre-eclampsia
• the placenta of a woman with this condition is often small with poor trophoblastic infiltration

Question 20

What are the risk factors for development of pre-eclampsia?

Answer 20

1. BMI > 35
2. pre-existing hypertension
3. renal disease
4. diabetes
5. lupus or antiphospholipid syndrome
6. previous pregnancy affected
7. family history of pre-eclampsia
8. maternal age > 40 or < 20
9. more than 10 years between pregnanies
10. multiple foetuses
11. first pregnancy

Question 21

What are the symptoms associated with pre-eclampsia?

Answer 21

1. headache
2. confusion
3. RUQ pain
4. respiratory symptoms - cough, chest pain, dyspnoea
5. visual disturbances
6. decreased urine output
7. N&V

Question 22

What is HELLP syndrome?

What condition is it associated with and what are the outcomes like?

Answer 22

• HELLP syndrome is defined as:

1. Haemolysis
2. Elevated Liver enzymes
3. Low Platelet count

• it occurs in 10-20% of cases of severe pre-eclampsia / eclampsia and is associated with increased maternal & foetal morbidity / mortality

Question 24

What are the main mechanisms for prevention of pre-eclampsia?

What treatments may be given to mothers who have developed this condition?

Answer 24

1. smoking cessation prior to pregnancy
2. calcium supplementation in areas with low intake
3. aspirin given to those deemed as high-risk
4. treatment of pre-existing HTN with medication

• delivery of the placenta is an effective treatment, but full recovery can take days/weeks
• blood pressure medication (e.g. labetalol / methydopa) is given to improve condition prior to delivery
• magnesium sulphate is given to prevent eclampsia in severe disease

Question 25

What is eclampsia? What are the warning symptoms for this and how is it managed?

Answer 25

* eclampsia involves the **development of _new convulsions_ in a pre-eclamptic patient** that cannot be attributed to other causes * warning symptoms for development of eclampsia include: 1. **headache** 2. **visual disturbances** 3. **RUQ / epigastric pain** * **_magnesium sulphate_** is given to **prevent convulsions** in patients with severe pre-eclampsia

Question 26

What is the normal diameter and length of the umbilical cord? What are the risks associated with a long umbilical cord?

Answer 26

* normal diameter is **1-2cm** and normal length is **50-60cm** * a long umbilical cord can **_encircle the neck of the foetus_** and have devastating consequences * it is also associated with an increased risk of: 1. **foetal entanglement** 2. **cord prolapse** 3. **true cord knots** these events can **_deprive the baby of oxygen during delivery_** and result in serious brain injuries

Question 27

What is the risk associated with an umbilical cord that is too short?

Answer 27

* it may pull the placenta away from the uterine lining, producing **_placental abruption_**

Question 28

What is meant by the "breech position"? What are the associated risks of this condition?

Answer 28

* this occurs when the **_buttocks or feet present first_**, opposed to the head (cephalic position) * this carries risks of **premature birth, asphyxiation / trauma during birth** and increased incidence of **congenital malformations**

Question 29

What is meant by umbilical cord prolapse? What are the risks associated with this condition?

Answer 29

* the **umbilical cord comes out of the uterus _with or before_ the presenting part of the baby** * the pressure exerted on the cord by the baby can **_compromise the blood flow_** that it receives * this usually occurs during labour, but can occur any time after rupture of the membranes

Question 30

What is the management for cord compression?

Answer 30

* quick delivery is required, usually by C-section * until this can take place, the woman is placed in a **_knee-chest position_** or **_Tredelenburg position_** (head down, feet elevated) to prevent further compression * a gloved hand may be inserted into the vagina to **push the foetus upwards and off the cord**

Question 31

Why can jaundice occur after birth? What can severe neonatal jaundice develop into?

Answer 31

* haemolysis of RBCs leads to **increased levels of bilirubin** * when the child is born, **_bilirubin is no longer cleared via the placenta_** and so symptoms of jaundice can increase within 24 hours after birth * severe neonatal jaundice can result in **_kernicterus_**, which can result in **brain damage**

Question 32

Why is the risk of kernicterus higher in haemolytic disease of the newborn?

Answer 32

* there is **massive and rapid destruction of RBCs**, elevating bilirubin levels more rapidly

Question 33

What is haemolytic disease of the newborn and how does it occur?

Answer 33

* **_IgG antibodies_** are produced by the mother (Rh -ve) when she is exposed to a **foreign antigen** * the IgG antibodies can **_cross the placenta_** and **target this antigen** if it is present within the foetus * in order for the mother to become sensitised, she needs to be **exposed to the antigen** via **_haemorrhage_** or **_blood transfusion_** * *haemorrhage occurs during birth, as well as abortion, ectopic pregnancy and ruptures of the placenta* * near the time of birth, the **IgG antibodies cross the placenta** and **_attack antigens on foetal RBCs_**, which destroys the cells

Question 34

How does the foetus respond to maternal IgG attacking the antigens on its RBCs?

Answer 34

* breakdown and destruction of foetal RBCs leads to **_reticulocytosis_** and **_anaemia_** * reticulocytosis involves the foetus **increasing RBC production** to compensate for the loss, but sends out **_immature RBCs_** **that still have nuclei** * the baby is often **_jaundiced_** at birth * if foetal anaemia is so severe that there is **oedema / effusion into body cavities**, this can result in **_foetal death from heart failure (hydrops fetalis)_**

Question 35

Why is haemolytic disease of the newborn more likely to occur in a subsequent pregnancy?

Answer 35

**_First exposure - birth of Rh+ infant:_** * during birth, **foetal RBCs can leak into maternal blood** after breakage of the embryonic chorion * *the chorion usually isolates maternal and foetal blood* * the mother produces **IgG antibodies against the Rh+ antigen** on the RBCs **_Second exposure - Rh+ foetus:_** * there are **IgG antibodies** present within the mother's blood following the first exposure * Rh antibodies can **cross the embryonic chorion / placenta** and attack the foetal RBCs

Question 36

What antigen is usually responsible for causing HDN? Where does this come from?

Answer 36

* it is most commonly triggered by the **_RhD antigen_** * A **Rh-D -ve mother** becomes pregnant with a **Rh-D +ve foetus** * the child has inherited the D antigen from the father * the mother's immune system forms **antibodies against the D antigen (anti-D)**

Question 37

How is HDN screened for?

Answer 37

through the **_direct and indirect Coomb's test_** **_Direct Coomb's test - used to diagnose HDN:_** * this detects anti-Rh antibody that has **already bound to foetal RBCs** **_Indirect Coomb's test - used in prevention of HDN:_** * this detects free anti-Rh antibody in **maternal blood serum** * by finding maternal anti-D antibodies **prior to attack** of foetal RBCs, treatment can be given to prevent or limit the severity of HDN

Question 38

What is the treatment in Rh-D -ve women who have not been sensitised (no anti-D antibody)?

Answer 38

the aim of treatment is to **_prevent sensitisation_** * **_anti-D IgG_** is given @ **28/40** which **"mops up" any foetal RBCs** that may have leaked into the maternal circulation * *this reduces the risk of first-time exposure to the D antigen* * another anti-D injection is given **within 72 hours of delivery**

Question 39

If a mother is found to be sensitised, what are the following steps?

Answer 39

**_Confirm the Rh status of the foetus:_** * if the father is homozygous for the D allele (D/D), then the foetus will be Rh-D +ve * if the father is **heterozygous (D/d**), then there is a **50% chance** the foetus is Rh-D +ve and a **sample of foetal cell**s are taken from the amniotic fluid or umbilical cord to test this **_If foetus is Rh-D +ve:_** * pregnancy is closely monitored for signs of HDN through **_regular USS_** and **_monitoring amount of anti-D_** in maternal serum * a rise in anti-D indicates **_active haemolysis_** * if a foetal blood test confirms **anaemia**, a **_blood transfusion_** is performed via the umbilical vein in utero to **replace lysed foetal RBCs**

Question 40

What is coarctation of the aorta? What are the 2 different types and what defines them?

Answer 40

* a congenital condition in which there is **_narrowing of the aorta_** (usually the arch) * it can be classified as **preductal** or **postductal** depending on whether the narrowing occurs **_prior to or after the ductus arteriosus_**

Question 41

What is meant by post-ductal coarctation of the aorta? What happens during development as a result of this?

Answer 41

* post-ductal coarctation happens **_after the ductus arteriosus_** * during development, a **_collateral circulation_** is established to bypass the narrowing * as part of this collateral circulation, the **_internal thoracic arteries are enlarged_** * this is **more common** than preductal

Question 42

What is meant by preductal coarctation of the aorta? What usually happens after birth as a result of this?

Answer 42

* the narrowing occurs **_before the ductus arteriosus_** * during development, the **ductus arteriosus compensates for the narrowing** and so **_no collateral supply_** is developed * after birth, the **ductus arteriosus usually _remains patent_**

Question 43

What happens if there is closure of the ductus arteriosus following birth in a preductal coarctation?

Answer 43

* obliteration of the ductus arteriosus causes **rapid decline of the infant** with **_hypoperfusion of the lower body_** * this is due to **failure to establish a collateral circulation** during development

Question 44

What is Edward's syndrome caused by? How common is it?

Answer 44

* Edward's syndrome occurs as a result of **trisomy 18** * it affects 1 in 5000 live births

Question 45

What are the main prominent features of Edward's syndrome?

Answer 45

* **low birth weight** * **congenital heart defects** * **micrognathia** and **microcephaly** * **clenched fists with overlapping fingers** * **severe intellectual disability** * **omphalocele** * **low-set malfored ears** * cleft lip/palate * rocker bottom feet * widely spaced eyes * narrow eyelid openings

Question 46

What causes Patau syndrome? How common is it and what is the prognosis?

Answer 46

* it is caused by **_trisomy 13_** * it affects 1 in 10,000 - 21,000 live births but 90% of those affected die within the first year of life * those that do survive have severe disablement, seizures and psychomotor issues

Question 47

What are the main features of Patau syndrome?

Answer 47

* there is extreme variability in the presentation of foetuses with Patau syndrome and many features are similar to those seen in Edwards syndrome 1. polydactyly 2. proboscis 3. low-set ears 4. rocker bottom feet 5. omphalocele 6. overlapping of fingers over the thumb 7. cleft palate 8. myelomeningocele 9. eye defects 10. microcephaly 11. single umbilcal artery 12. kidney / genital / heart defects

Question 48

What causes Prader-Willi syndrome? What are the key features of this disorder?

Answer 48

* it is caused by a **_microdeletion on chromosome 15_** * in newborns, there is hypotonia, slow development and poor feeding * in childhood, those affected become constantly hungry, resulting in obesity and T2DM * there is mild-to-moderate intellectual impairment and behavioural problems * most have small hands / feet, short height and are infertile